HyperGEN: Genetics of Left Ventricular Hypertrophy

描述(由申请人提供)：左心室(LV)重构和肥厚在普通人群中频繁发生，是心肌梗死、心力衰竭和中风的强烈预测因素。此前在家庭血压计划(FBPP)的HyperGEN和Genoa研究中收集的数据表明，通过连锁研究和全基因组关联研究，基因座对左室肥厚和尺寸特征起作用。尽管取得了这些进展，但LV性状的很大一部分变异仍未得到解释。我们假设，在一定程度上，罕见的变异可以解释这种变异。我们提出了以下目标。 目的1.对1200例Aa无关高血压患者超声心动图LV质量/hgt2.7极值的完整外显子序列(WES)进行分析，以确定导致LV质量的罕见和低频变异及其相关的结构和功能表型。我们将从LV质量指数的顶部和底部四分位数中选择不相关的个体。由于左心室质量/hgt2.7在FBPP中的分布向高于一般人群的值移动，上四分位数的切点近似等于LVH的定义。我们将以足以捕获稀有变异的密度进行测序。我们将进行基于极端表型的分析，按功能和保守性加权，以确定高影响的编码变体。根据统计和生物信息学分析的证据，以及诱导多能干细胞(IPSC)来源的心肌细胞的表达实验，将在AIM 2中对基因列表进行选择。目的2.通过对所有AA HyperGEN/Genoa家族成员中的40个候选基因重新测序，验证在AIM 1中检测到的变异，并随后验证外部队列中最显著的768个变异。我们将对目标1(n=2,266)中未测序的FBPP家族和兄弟姐妹中的所有外显子和调节区进行测序。我们将进行关联分析，然后进行生物信息过滤，以确定高影响的编码变体，并对768个最重要的变体进行排名，以供进一步外部复制。我们将使用Illumina分析方法(即JHS、CARDIA、ARIC、CHS、WUSTL)对9,160名AA(5,623名高血压)参与者进行这些基因分型。基于基因的关联将在队列内进行检查，并在队列中进行荟萃分析。基因将通过统计学和生物学证据进行排序，以转移到Aim 3。Aim 3.使用人iPSC心肌细胞从功能上验证在Aim 2中复制的变体。使用肥大诱导的心肌细胞，我们将测试Aim 2中罕见变异的相关基因的作用方向和临床特征。我们将使用siRNA转染来测试在基于细胞的模型中候选基因的敲除是否影响肥大。这里提出的研究，如果成功，将继续HyperGEN和Genoa在识别导致左室肥厚的新基因方面的成功，并评估它们在基于细胞的系统中的相关性，以确定未来治疗的新途径。

DESCRIPTION (provided by applicant): Left ventricular (LV) remodeling and hypertrophy occurs frequently in the general population and is a strong predictor of myocardial infarction, heart failure, and stroke. Data previously collected in the HyperGEN and GENOA studies of the Family Blood Pressure Program (FBPP) have pointed to genetic loci contributing to LV hypertrophy and dimensional traits through linkage studies and genome-wide association studies. Despite these advances, a large portion of variation in LV traits is unaccounted for. We hypothesize that, in part, rare variants account for this variation. We propose the following aims. Aim 1. Whole exome sequence (WES) 1,200 AA unrelated hypertensives with extreme values for echocardiographic LV mass/hgt2.7 to identify rare and low-frequency variants contributing to LV mass and related structural and functional phenotypes. We will select unrelated individuals from the top and bottom quartile of LV mass index. Because the distribution of LV mass/hgt2.7 in the FBPP is shifted to higher values than the general population, the cutpoint for the upper quartile is approximately equal to the definition of LVH. We will sequence at a density sufficient to capture rare variants. We will conduct extreme phenotype-based analysis, weighted by function and conservation, to identify high-impact coding variants. A gene list will be ranked for selection in Aim 2 based on evidence from statistical and bioinformatic analyses and expression experiments in induced pluripotent stem cell- (iPSC-)derived cardiomyocytes. Aim 2. Validate variants detected in Aim 1 by resequencing 40 candidate genes in all AA HyperGEN/GENOA family members, and subsequently validate 768 most significant variants in external cohorts. We will sequence all exons and regulatory regions in the remainder of the FBPP families and siblings not sequenced in Aim 1 (n=2,266). We will conduct association analysis followed by bioinformatic filtering to identify high-impact coding variants and rank the 768 most significant variants for further external replication. We will genotype these in 9,160 AA (5,623 hypertensive) participants from population-based studies using Illumina assays (ie, JHS, CARDIA, ARIC, CHS, WUSTL). Gene-based associations will be examined within and meta-analyzed among cohorts. Genes will be ranked by statistical and biological evidence to move to Aim 3. Aim 3. Use human iPSC cardiomyocytes to functionally validate variants replicated in Aim 2. Using hypertrophy-induced cardiomyocytes, we will test the direction of effect and clinical characterization of associated genes with rare variants from Aim 2. We will use siRNA transfections to test whether knock down of candidate genes influences hypertrophy in the cell-based model. The research proposed herein, if successful, will continue the success of HyperGEN and GENOA in identifying novel genes contributing to LV hypertrophy, and evaluate their relevance in a cell-based system to identify new pathways for future treatment.